Its abbreviation is HMD. A computermonitor, or other display, which is worn on the head. An HMD may display to one or both eyes, and may be in the form of goggles, a helmet, or the like. When displaying for one eye, for instance, it allows a user to view it without looking away from the surrounding environment, which is useful in many technical and scientific applications. When displaying to both eyes, it is especially suited for immersion in virtual reality environments. An HMD often has other associated devices working alongside, such as a microphone and earphones.